ASTM A1009-18

Standard Specification for Soft Magnetic MnZn Ferrite Core Materials for Transformer and Inductor Applications

ABSTRACT
This specification deals with soft magnetic manganese zinc ferrite core materials for high frequency power transformer and filter inductor applications. Standard types of both power transformer and filter inductor material are defined. For power transformer use, there are five types defined by their maximum core loss density and minimum saturation flux density. For filter inductor materials, three types are defined based on their inductance permeability. Apart from magnetic property requirements, dimensional tolerances and workmanship requirements are defined in this specification.
SCOPE
1.1 This specification covers the requirements to which the specified grades of soft magnetic manganese zinc (MnZn) ferrite materials shall conform. Cores made from these materials are used primarily in transformers and inductors.  
1.2 Frequency—MnZn ferrite cores are primarily used for frequencies in the range of 10 kHz to 1 MHz. Many inductors have a DC component as well.  
1.3 Magnetic Flux Density—Applications consist of two main categories, high and low magnetic flux density.  
1.3.1 High Magnetic Flux Density—Transformers used for power conversion. Inductors or chokes used in high current applications.  
1.3.2 Low Magnetic Flux Density—Transformers, inductors, chokes used for signal conditioning.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to customary (cgs-emu and inch-pound) units, which are provided for information only and are not considered standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2018
• ICS: 29.100.10 - Magnetic components
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.02 - Material Specifications

Relations

• Refers: ASTM A340-23a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Dec-2023
• Refers: ASTM A1013-00(2020) - Standard Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components at Controlled Temperatures Using the Voltmeter-Ammeter-Wattmeter Method
• Effective Date: 01-Jun-2020
• Refers: ASTM A340-19b - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Oct-2019
• Refers: ASTM A340-19a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Jun-2019
• Refers: ASTM A340-19 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Feb-2019
• Refers: ASTM A340-18 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Jun-2018
• Refers: ASTM A340-17a - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 15-Oct-2017
• Refers: ASTM A340-17 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Jul-2017
• Refers: ASTM A340-16e1 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2016
• Refers: ASTM A340-16 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2016
• Refers: ASTM A340-15 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Oct-2015
• Refers: ASTM A340-14 - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-Oct-2014
• Refers: ASTM A1013-00(2013)e1 - Standard Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components at Controlled Temperatures Using the Voltmeter-Ammeter-Wattmeter Method
• Effective Date: 01-May-2013
• Refers: ASTM A340-03a(2011) - Standard Terminology of Symbols and Definitions Relating to Magnetic Testing
• Effective Date: 01-May-2011
• Refers: ASTM A1013-00(2005) - Standard Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components at Controlled Temperatures Using the Voltmeter-Ammeter-Wattmeter Method
• Effective Date: 01-Nov-2005

Overview

ASTM A1009-18: Standard Specification for Soft Magnetic MnZn Ferrite Core Materials for Transformer and Inductor Applications provides guidelines for the classification, requirements, and testing of soft magnetic manganese zinc (MnZn) ferrite core materials. These core materials are designed specifically for high-frequency power transformers and filter inductors, with a frequency range of 10 kHz to 1 MHz. The standard establishes material types by their maximum core loss density, minimum saturation flux density, and relative inductance permeability, supporting the efficient performance and reliability of electrical and electronic devices.

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Key Topics

• Core Material Types:

  • Defines material grades for power transformers and filter inductors
  • Power transformer materials are categorized by maximum core loss density and minimum saturation flux density
  • Filter inductor materials are defined by their relative inductance permeability

• Magnetic Property Requirements:

  • Specifications for high and low magnetic flux density applications
  • Requirements for maximum core loss density in power applications
  • Guidelines for relative permeability in filter inductor applications

• Mechanical and Dimensional Requirements:

  • Standardized tolerances for sintered and machined dimensions
  • Specifications for the finish, appearance, and defect limitations on core surfaces

• Testing and Reporting:

  • Methods for magnetic property measurements, including inductance index (AL value), permeability, and core loss density
  • Requirements for lot identification and material certification reporting

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Applications

The ASTM A1009-18 standard is essential for manufacturers, designers, and users of soft magnetic ferrite cores in the electrical and electronics industry. Key application areas include:

• High-frequency Power Transformers:
  Ensures that transformer cores meet strict magnetic and mechanical standards for efficiency and reliability in power conversion applications.

• Filter Inductors:
  Provides material guidance for cores used in filters, supporting noise reduction and signal integrity in electronic circuits.

• Inductors and Chokes:
  Covers both high-current and signal conditioning roles, ensuring that cores maintain consistent performance across varying flux density requirements.

• Custom Electronic Components:
  Standards for customized core shapes, gapping, and inductance values support specialized applications in advanced electronic designs.

Using ASTM A1009-18 improves the predictability and quality of ferrite cores in critical roles, helping manufacturers and engineers optimize electrical performance, reduce losses, and ensure product consistency.

---

Related Standards

• ASTM A340:
  Terminology of Symbols and Definitions Relating to Magnetic Testing
  Reference for magnetic property terms used throughout ASTM A1009-18.

• ASTM A1013:
  Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components
  Specifies the core loss testing procedures required for compliance.

• IEC Ferrite Standards:
  International specifications for ferrite materials and testing methods, providing a global context.

For optimal results in high-frequency transformer and inductor applications, ASTM A1009-18 should be used in conjunction with these related standards to ensure complete, compatible, and robust implementation.

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Keywords: ASTM A1009-18, MnZn ferrite core, soft magnetic materials, high frequency transformers, filter inductors, core loss density, permeability, power electronics standards, magnetic properties, material specification.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:A1009 −18
Standard Specification for
Soft Magnetic MnZn Ferrite Core Materials for Transformer
and Inductor Applications
This standard is issued under the fixed designation A1009; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This specification covers the requirements to which the 2.1 ASTM Standards:
specified grades of soft magnetic manganese zinc (MnZn) A340 Terminology of Symbols and Definitions Relating to
ferrite materials shall conform. Cores made from these mate- Magnetic Testing
rials are used primarily in transformers and inductors. A1013 Test Method for High-Frequency (10 kHz-1 MHz)
Core Loss of Soft Magnetic Core Components at Con-
1.2 Frequency—MnZn ferrite cores are primarily used for
trolled Temperatures Using the Voltmeter-Ammeter-
frequencies in the range of 10 kHz to 1 MHz. Many inductors
Wattmeter Method
have a DC component as well.
1.3 Magnetic Flux Density—Applications consist of two 3. Terminology
main categories, high and low magnetic flux density.
3.1 The terms and symbols used in this specification are
1.3.1 High Magnetic Flux Density—Transformers used for
defined in Terminology A340.
power conversion. Inductors or chokes used in high current
3.2 Definitions of Terms Specific to This Standard:
applications.
3.2.1 air core inductance (L )—theA value, assuming an
air L
1.3.2 Low Magnetic Flux Density—Transformers,inductors,
effective permeability of one. A is proportional to the factors
L
chokes used for signal conditioning.
of shape and size of the core. The air core inductance is
1.4 The values stated in SI units are to be regarded as 2
expressed as nanohenries per turn squared (nH/N ).
standard. The values given in parentheses are mathematical
L 5 µ A ⁄L (1)
air o e e
conversions to customary (cgs-emu and inch-pound) units,
whichareprovidedforinformationonlyandarenotconsidered
where:
standard. 2
A = effective cross-sectional area of core in mm ,
e
1.5 This standard does not purport to address all of the
L = effective magnetic path length of core in mm, and
e
µ = the magnetic constant as 0.4 π nH/mm.
safety concerns, if any, associated with its use. It is the
o
responsibility of the user of this standard to establish appro-
3.2.2 effective initial permeability (µ )—the initial perme-
c
priate safety, health, and environmental practices and deter-
ability of the material as defined in A340, adjusted for known
mine the applicability of regulatory limitations prior to use.
processing variables that are not accounted for in the L term
air
1.6 This international standard was developed in accor-
such as mating surface finish and heat treatment. Can vary with
dance with internationally recognized principles on standard-
size, shape, and material.
ization established in the Decision on Principles for the
3.2.3 inductance index (A value)—the inductance normal-
L
Development of International Standards, Guides and Recom-
ized for the number of turns. Is proportional to the factors of
mendations issued by the World Trade Organization Technical
effective initial permeability of the material core, shape, and
Barriers to Trade (TBT) Committee.
size. It allows quick determination of expected inductance
when used with the number of turns on the winding of the
This specification is under the jurisdiction of ASTM Committee A06 on
Magnetic Propertiesand is the direct responsibility of Subcommittee A06.02 on
Material Specifications. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2018. Published November 2018. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2000. Last previous edition approved in 2010 as A1009 – 05 (2010). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/A1009-18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A1009−18
TABLE 2 Low Magnetic Flux Density Material Type Designations
intended application. The inductance index is expressed as
2 and Magnetic Requirements
nanohenries per turn squared (nH/N ):
A
ASTM Filter
Relative Inductance Permeability
A 5 L µ (2)
L air e µ
Material L
And therefore the expected inductance (L) is:
Type Minimum Nominal Maximum Tolerance
F010K 7000 10 000 13 000 ±30 %
L 5 A N (3)
L
F7000 4900 7000 9100 ±30 %
F5000 3750 5000 6250 ±25 %
where:
F3000 2500 3000 3750 ±25 %
-9
nH = inductance in nanohenries, 10 Henries, A
Relative inductance permeability test conditions 100 kHz, 0.5 mT (5 gauss), at
N = the number of turns of winding,
25°C.
L = the expected inductance, for a givenA and number of
L
turns.
3.2.4 mated core set—twoormorecoresegmentsassembled
with the magnetic flux path perpendicular to the mating
5.1.4 Whether the core is to be purchased with or without a
surface.
gap.
5.1.4.1 The Inductance Index (AL value) or the mechanical
4. Classification
gap depth.
4.1 The soft magnetic MnZn ferrite material-type designa-
5.1.4.2 If the mated core set is ordered gapped by an
tions for high and low magnetic flux density materials covered Inductance Index (AL value), the purchaser must specify
by this specification are listed in Table 1 and Table 2. The
whetherthematedcoresetconsistsofagappedcorehalfmated
prefix of the type designations identifies each material’s with an un-gapped core half or if both core halves are equally
intended use. High magnetic flux density materials are denoted
gapped.
with the prefix P and low magnetic flux density materials are 5.1.4.3 If the mated core set is ordered gapped by an
denoted with the prefix F. Inductance Index (AL value), the purchaser must supply the
producer with a test coil and the testing conditions (circuit
4.2 High Magnetic Flux Density Materials—The first and
mode, turns on coil, frequency, and magnetic flux density).
second digits of the type designations identify the typical core
5.1.4.4 The tolerance of either the Inductance Index (AL
loss density of the material in kW/m , and the remainder of the
value) or the mechanical gap depth.
type designation identifies the temperatures in °C in which the
5.1.5 Quantity in pieces.
core material must not exceed the maximum core loss density.
5.1.6 Exceptions to the specification or special require-
4.3 Low Magnetic Flux Density Materials—The last four
ments.
digits of the type
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A1009 − 05 (Reapproved 2010) A1009 − 18
Standard Specification for
Soft Magnetic MnZn Ferrite Core Materials for High
Frequency (10 kHz-1 MHz) Power Transformer and Filter
Inductor Applications
This standard is issued under the fixed designation A1009; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers the requirements to which the specified grades of soft magnetic manganese zinc (MnZn) ferrite
materials shall conform. Cores made from these materials are used primarily in power transformers and filter inductors.
1.2 Frequency—MnZn ferrite cores are primarily used for frequencies in the range of 10 kHz to 1 MHz. Many inductors have
a DC component as well.
1.3 Magnetic Flux Density—Applications consist of two main categories, high and low magnetic flux density.
1.3.1 High Magnetic Flux Density—Transformers used for power conversion. Inductors or chokes used in high current
applications.
1.3.2 Low Magnetic Flux Density—Transformers, inductors, chokes used for signal conditioning.
1.4 The values stated in customary (cgs-emu and inch-pounds) SI units are to be regarded as standard. The values given in
parentheses are mathematical conversions to SI customary (cgs-emu and inch-pound) units, which are provided for information
only and are not considered standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A1013 Test Method for High-Frequency (10 kHz-1 MHz) Core Loss of Soft Magnetic Core Components at Controlled
Temperatures Using the Voltmeter-Ammeter-Wattmeter Method
3. Terminology
3.1 The terms and symbols used in this specification are defined in Terminology A340.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 Inductance Index (AL value)—the self inductance per winding turn squared (L/N ) expressed in units of nanohenries per
turns squared (nH/N ).
where:
–9
n = nano = 10 ,
nH = inductance in nanohenries, and
This specification is under the jurisdiction of ASTM Committee A06 on Magnetic Propertiesand is the direct responsibility of Subcommittee A06.02 on Material
Specifications.
Current edition approved Nov. 1, 2010Oct. 1, 2018. Published December 2010November 2018. Originally approved in 2000. Last previous edition approved in 20052010
as A1009 – 05.A1009 – 05 (2010). DOI: 10.1520/A1009-05R10.10.1520/A1009-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A1009 − 18
2 2 2
N = number of turns on winding (example: 0.005 H with a 100 turn coil = 0.005 ⁄(100) H/N = 500 nH/N ).
3.2.2 Mated Core Set—Two or more core segments assembled with the magnetic flux path perpendicular to the mating surface.
3.2.3 Air core inductance, L , is the inductance of a core with the same magnetic path length and cross-sectional core area but
air
with the relative permeability of air.
3.2.3.1 Customary Units
2 29
L 5 4ΠAN 10 /l , H
air 1
where:
N = number of turns on winding;
A = cross-sectional area of core specimen, cm ; and
l = effective magnetic path length, cm.
3.2.3.2 SI Units
2 27
L 5 4ΠAN 10 /l , H
air 1
where:
N = number of turns on winding;
A = cross-sectional area of core specimen, m ; and
l = effective magnetic path length, m.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air core inductance (L )—the A value, assuming an effective permeability of one. A is proportional to the factors of
air L L
shape and size of the core. The air core inductance is expressed as nanohenries per turn squared (nH/N ).
L 5 μ A ⁄L (1)
air o e e
where:
A = effective cross-sectional area of core in mm ,
e
L = effective magnetic path length of core in mm, and
e
μ = the magnetic constant as 0.4 π nH/mm.
o
3.2.2 effective initial permeability (μ )—the initial permeability of the material as defined in A340, adjusted for known
c
processing variables that are not accounted for in the L term such as mating surface finish and heat treatment. Can vary with size,
air
shape, and material.
3.2.3 inductance index (A value)—the inductance normalized for the number of turns. Is proportional to the factors of effective
L
initial permeability of the material core, shape, and size. It allows quick determination of expected inductance when used with the
number of turns on the winding of the intended application. The inductance index is expressed as nanohenries per turn squared
(nH/N ):
A 5 L μ (2)
L air e
And therefore the expected inductance (L) is:
L5 A N (3)
L
where:
-9
nH = inductance in nanohenries, 10 Henries,
N = the number of turns of winding,
L = the expected inductance, for a given A and number of turns.
L
3.2.4 mated core set—two or more core segments assembled with the magnetic flux path perpendicular to the mating surface.
4. Classification
4.1 The soft magnetic MnZn ferrite material-type designations for power transformer and filter inductor high and low magnetic
flux density materials covered by this specification are listed in Table 1, Table 2, and and Table X1.12. The prefix of the type
designations identifies each material’s intended use. Power transformer High magnetic flux density materials are denoted with the
prefix P and filter low magnetic flux density materials are denoted with the prefix F.
4.2 High Magnetic Flux Density Materials—The first and second digits of the type designations for a power transformer
material identify the typical core loss density of the material in mW/cmkW/m , and the remainder of the type designation identifies
the temperatures in °C in which the core material must not exceed the maximum core loss density.
4.3 Low Magnetic Flux Density Materials—The last four digits of the type designations for filter materials identify the typical
relative inductance permeability.
A1009 − 18
TABLE 1 Power Transformer Material Type Designations and
Magnetic Requirements
Specified
Temperatures
That Core
Maximum Core Loss Minimum Saturation Flux
Loss Density
ASTM A B
Density Density
Must Not
Power
Exceed
Material
Maximum
Type
Customary
SI Units, SI Units, Customary
Units, mW/ SI Units, T
W/m °C Units, G
cm
P5025-100 65 65 000 25-100 5000 0.5
P5099 65 65 000 99 5000 0.5
P7070 80 80 000 70 5000 0.5
P7099 80 80 000 100 5000 0.5
P8040 90 90 000 40 5000 0.5
TABLE 1 High Magnetic Flux Density Material Type Designations
and Magnetic Requirements
Saturation
ASTM
A
Core Loss Density Flux
Power Temperature
3 3
B
kW/m (mW/cm )
Density
Material °C
mT (gauss)
Type
Nominal Maximum Minimum
P5025-100 50 (50) 65 (65) 25–100 500 (5000)
P5099 50 (50) 65 (65) 100 500 (5000)
P7070 70 (70) 80 (80) 70 500 (5000)
P7099 70 (70) 80 (80) 100 500 (5000)
P8040 80 (70) 90 (90) 40 500 (5000)
A
Core loss density test conditions: 100 kHz, 1000 G (0.1 T) at temperature of
minimum core loss.100 mT (100 gauss), at specified temperature.
B
Saturation flux density test conditions: 1 kHz, 15 Oe (1200 A/m),1200 A/m (15
Oe), at 25°C.
TABLE 2 Filter Inductor Material Type Designations and Magnetic
Requirements
Minimum Maximum
Relative Relative
ASTM Filter
Inductance Inductance
Material Type
A A
Permeability, Permeability,
μ μ
L L
F010K 7000 13 000
F5000 3750 6 500
F3000 2250 3 900
TABLE 2 Low Magnetic Flux Density Material Type Designations
and Magnetic Requirements
A
ASTM Filter Relative Inductance Permeability
μ
Material L
Minimum Nominal Maximum Tolerance
Type
F010K 7000 10 000 13 000 ±30 %
F7000 4900 7
...